Self-regulating automatic traffic control system



Oct. 29, 1940. H. A. HAUGH. JR Z ,3

SELF-REGULATING AUTOMATIC TRAFFIC cou'mon srs'rsm Filed Oct. 20, 1927 4Sh eets-Sheat 1,

A Street Fig. 1

B Street Y I /n vefi or.- HenryAHaug/yJn ttorney.

2 1949- H. A. HAUGH. JR 22 9.

SELF-REGULATING AUTOMATIC TRAFFIC GQN' KROL SYSTEM Filed 001;, 20,19.217 4 Sheets-Sheet 2 Inventor.

' fl- Henry A.Haugh.J/:

I %orney.

I To Fire Headquarters 0d. 29, 1940. HAUGH, JR 2,219,310

SELF-REGULATING AUTOMATIC TRAFFIC CQNTRQLI SYSTEM 4 Sheets-Sheet 5WRNNRQbQQYMt Mkt 0k Filed Oct. 20, 1927 Oct. 29, 1940. H. A. HAUGH. JR2,219,310

SELFREC-ULATING AUTOMATIC TRKFFIC GONTROL SYSTBM 'Filed Oct. 20, 192 7 4Sheets-Shet 4 in mm tor:

' Henry/4. Hau hJr:

Ai iom ey Patented Oct. 29, 1940 UNITED STATES I SELF-REGULATINGAUTOMATIC TRAFFIC CONTROL SYSTEM Henry A. Haugh, Jr.,

by mesne assignments, Research Corporation,

New Haven, Conn, assignor,

to The Engineering and East Norwalk, Conn, a

corporation of Delaware I Application October 20, 1927, Serial No.227,490

39 Claims.

This invention relates to automatic self-regulating traflic controlsystems and more particularly to a system for controlling vehiculartrailic at highway intersections. A traflic control sys- 5 tem embodyingmy invention is not limited in its use to the regulation of highwaytraflic but may be employed with equal facility at any intersecting'trafflc lanes wherein it is desired to automatically regulate thepassage of trafllc through the intersection by the presence of vehiclesdesiring to use the intersection. Such a system may be employed atrailway crossings where it is desired to operate any convenient warningsignal. v One fault of the ordinary stop and go installation employingsignals for street traflic control, and regulated by a timing devicewhich exhibits the signals in a periodic sequence without regard totraffic conditions, is that it frequently happens that the stop signalis turned against moving vehicles, in order to give the right of way tothe trafllc on the intersecting street when there are no waitingvehicles thereon. Another fault with such ordinary timed systems is thatthe right of way is retained on a street longer ,0 than required,causing vehicles on the .other street to wait needlessly. Theseconditions needlessly delay traffic, and cause congestion atintersections. The primary object of my invention is to provide a self-regulating traflic control system which shall be mechanically dependentupon actual .volume and distribution'of traflic. This object isaccomplished by providing a mechanical system of traffic control whichshall function in response to the particularcondition of traflic' flow,and operate the desired signal in response to the actual volume anddistribution of traflic rather than upon any arbitrary time setting.

A further object of my invention is to provide a system of trafliccontrol wherein an indicating signal is operated by the trafllc througha timing mechanism, by the timing mechanism itself, or by both, in sucha way:

1. That right of way is given successively to sev- 7 eraltraflic lanesin an order which maybe pre-- determined but in such a way that thelength of time which one lane retains the right of way is dependent uponeither the approach of vehicles in said lane, upon the approach ofvehicles in one or more other lanes, or upon both.

2. That a traflic lane which does not require the right of waycannothold it to the disadvantage of one which does.

3. That a vehicle whose progress is prevented by acontinuous stream ofopposing tramc may I means right not be required to wait more than afixed period of time, but that within this period is given right of wayfor as long as required for itself and fol- I lowing vehicles up to theaforementioned time 5 limit.

4. That interfering lanes of trafllc shall not be permitted to hold theright of way simultaneously.

5. That a vehicle which has passed the actuating means is protectedagainst opposing traflic for a period of time suflicient to permit thesaid vehicle to pass the intersection of the trafllc lanes. I

6. That a vehicle which approaches an intersection on any lane oftrafllc is given immediate right of way on condition and only oncondition that there be no opposing traffic in or immediatelyapproaching the intersection.

7. That when a vehicle is not given immediate right of way or has rightof way taken from it before it has had sufficient time to reach theintersection, the system will be left in such a condition that right ofway will return to the delayed car at the earliest possible moment.

8. That continuous vehicular'trafllc in one lane is periodicallyinterrupted to allow pedestrians to cross this lane even in the absenceof vehicular traflic in the lane of the pedestrians.

9. That when the signal means and timing system is disconnected from thetrafllc actuated of way is given successively to the various trafficlanes according to a predetermined sequence and each for a predeterminedtime interval,

10. That by simple adjustments in the system, all fixed time intervalsand responses to traflic in various lanes may be adjusted to meetvarious distributions and densities of traflic.

Other objects will be more manifest by reference to the followingspecification and drawings and specifically set forth in the claims.

In the drawings:

Fig. l is a diagrammatic view showing a highway intersection employing asignal system em bodying my invention.

Fig.2 is a diagrammatic view showing the circuits of an apparatus foroperating the signal at intersecting traflic lanes.

Fig. 2a is an across the line arrangement Fig. 2.

Fig. 3 is a detail view showing a section of a vehicle actuated contactdevice.

Fig. 4 is a wiring diagram for two cont-act devices in a traffic lane,and located at opposite sides .of the intersection.

and red, yellow,

' side of the street a flow of gas or liquid A self-regulating automatictramc control system embodying my invention comprises three parts, avehicle indicator placed in or at the side of the road, an electricaltime limiting control system, and a signal device to indicate right ofway to tramc. The function of the indicating device is such that avehicle approaching the intersection of two or more traffic lanesactuates an electrical control circuit. The function of the electricaltime limiting control system is to receive actuation produced by thevehicle and to pass this actuation on either instantly or after thepassage of some timed period to the signal means which shall then warnthe vehicle either to stop or shall give it the right of way. The nalmeans to inform the trafiic in each street when to go and when to stopmy be and green lights now in general use, and these are mentioned inthis description, but other means such as semaphore arms, horns, orbells or any other signal means may be used with equal facility. Thevehicle actuated means may be of several types as hereinafter mentioned:

One means actuated by the approaching vehicle may be of a mechanicalnature such as a mechanical switch located in the street or at the andelectrical contact being made upon passage of the vehicle.

Another means for detecting and recording the presence of an approachingvehicle may be any beam of light projected across the highway andreceived upon a photo-electric or light sensitive electric cell so thatan approaching vehicle causes an interruption or fluctuation in ancurrent passing through photo-electric cell.

An electromagnetic device located in the street or at the side of thestreet may also be arranged in such a manner that an approaching vehicleshall actuate the device to interrupt an electric circuit.

The approaching vehicle may be caused to pass over a flexible tubeplaced across the highway, said tube containing a' gas or a liquid. Thevehicle crossing this tube could either interrupt within the tubetherebycausing a mechanical switch to actuate the electrical circuit, or itmight operate the mechanical switch merely through the accompanyingchange electrical the light sensitive or of pressure in-a static gas orliquid in the flexible tube.

The time limit control circuit operates as follows: Assume that thereare no vehicles approaching on the intersecting streets designated by Aand B; a yellow signallight appears in both streets. A- vehicleapproaching from A-street now operates the A-street actuating means andcontact relays immediately close the circuit, thus lightingtheA-street-green and the B-street-red lights and simultaneouslyextinguishing the yellow lights in both streets. A-street now has theright of way. The device provides for relinquishing the A-street greenlight under any one of 1. WhenA-street traffic has all passed theintersection.

2. If A-street tramc is still moving at the end of a predeterminedperiod (such as 30 seconds) the green light is yielded to permitpedestrians to'cross A-street.

3; If A-street trailic is still moving at the end of the 30 secondperiod and vehicles arewaiting on B-street, the A-street green light isyielded in favor of B street.

the standto A-street. If there is no either street the lights in bothstreets continue to show yellow until a vehicle approaches. Right Theselimitations on the period during which A-street may hold the greenlight, are controlled by suitable time limit relays hereinafter described.

Provision to yield the A-street green light whenever the A-streettrafilc has passed the intersection (case 1 above) is made through theuse of a time limit relay set to open the A street-green and theB-street-red light circuit, after said relay has been continuouslyenergized for a predetermined period, as for example, seconds. Thisrelay is set back to its starting position at each time a vehicleoperates the A- street actuating means. Hence if a small number ofvehicles requiring the use of this interr set back to its startingposition; thus preventing it from interrupting the A-street-green andthe B-street red light circuit. Under these conditions another timelimit relay set for a predetermined period, say a thirty second period,functions. vThe action of this relay is described in the next paragraph.

To provide for case 2 mentioned above, in which continuous traffic onA-street must be interrupted to permit pedestrians to cross A-street,another time limit relay set to open the A-street green and the B-streetred light circuit is connected so that it will be energized whenA-street is given the green light. back to its starting point byvehicles passing the A-street actuating means. Hence it yields theright'of way held by A-street seconds after said right of way was given,unless the ten second relay had previously functioned due to thecessation of A-street traffic.

The combined effect of these, time limit relays causes A-street to holdthe green light for the full 30 second period only if trafllc onA-street requires it, yielding said light before the 30 second periodexpires if all the A-street traffic has passed the intersection.

The control circuit is A-street has yielded the green light under any ofthe above outlined conditions a yellow light is shown in both streetsduring a caution period. After the caution period waiting trafficdetermines which street is to get the right of way. If traflic waits onboth streets, that on B-street is given the green light. If there iswaiting traffic on A-street only, the green light reverts of way is thengiven immediately to the appreaching vehicle. In the next paragraph thisis expressed in terms of. the functioning of the actual apparatus.

If at the end of this yellow caution period,

vehicles have operated the B-street actuating means since 10 secondsbefore said street last lost the right of way, the green light is givento B- street. If on-the other hand no vehicles have operated theB-street actuating means since 10 seconds before B-s'treet last lost thegreen light, and vehicles have operated the A-street actuating meanssince 10 seconds before A-street last lost so arranged that when Thisrelay is not set traflic waiting on the green light, right of wayreturns to A-streeteffect of a wheel passing over a ramp in A-streetafter the yellow caution period. If the actuating means in neitherstreet has been operated since 10 seconds before said street last lostthe green light, the yellow lights will remain lighted on both streetsuntil a vehicle approaches. Right of way is then immediately given to anapproaching ve hicle on either. street.

A vehicle might approach the intersection from A-street during the lastfew seconds of A-streets 30 second period. The light might shift aftersaid vehicle had crossed the actuating means but before it had crossedthe intersection thereby stranding said vehicle between the actuatingmeans and the crossing. To permit a vehicle so stranded to pass as soonas possible'the circuit is so arranged that the operation of theA-street actuating means during the 10 seconds directly preceding theyielding of the A-street green light (when yielded by the 30 secondrelay only) causes the green light to revert .to A-street at the firstopportunit thereby releasing the stranded vehicle. For-this reason, thephrase in the preceding paragraph is worded since 10 seconds before saidstreet last lost the green light.

In this description time limit relays operating to limit the periodduring which'A-street may hold the right of way were mentioned. Anotherset similar to that used to govern A-street would be provided to governB-street when B-street should have the right of way. Their operation isjust as that described in the case of the A-street relays.

There is included in the relay system a pair of time limit relays set tooperate after they have been energized for a predetermined interval, for

example, 2 seconds. The function of these relays is to govern the lengthof the cautionary period between the red and green light period.

While I have described above a self-regulating automatic traflic controlsystem embodying my invention, and have shown that this inventionis-comprised of three main interconnected parts, I now describe indetail the construction of one complete and specific system embodying myinvention. Referring to Fig. l of the drawings there is shown a completeself-regulating automatic traflic control system applied to intersectingstreets Aand B. The vehicle actuated means are indicated by numbers 4,I, 0. and 1. The signalmeans in this particular embodiment is indicatedat 9, and contains a red and a green electric lamp visible from eitherdirection on A- street butnot visible on B-street; a red and a greenelectric lamp visible from either direction on B-street, but not visiblefrom A-street: and a yellow electric 'lamp visible from both streets.Energy is supplied to these electric .lamps through the wires entering 9as will be more completely described later.

The electrical time limiting control is ind cated by 8. Fig. 1. Wiresl0. II and I 2' interconnect the A-street veh cle actuated means. whilewires I0, II, and I2 also connect these two means to the electrical timelimiting control. Wires I3, l4 and I5. interconnect the vehicle actuatedmeans on B-street, while wires I3, I4, and I5 also connect these twomeans to the electrical time limiting control. Figure 3 shows a vehicleactuated means constructed according to this part cular embodiment, andnumbers 90, 9|; 92, and 93 indicate electrical contacts, which are soarranged that when a vehicle passes over the ramp arm I04, this ramp andis pushed down, pivoting at I03, so that contacts 90 and 9| areseparated and contacts Hand 93 are brought together. The

is to open the circuit between wires II and I2 by separating contacts 90and 9|,and then make a circuit between wires l0 and II by contactbetween 92 and 93. When the wheel has passed, spring I03 causes arm I04to rise separating contacts 92 and 93 thereby opening the circuitbetween wires l0 and II and re-establishes contact a I between 90 and 9|thereby re-establishing connection between wires H and I2 throughcontacts 94 and.95 on theother ramp on A-street. Fig. 4 indicates theway in which the two vehicle actuated means on any one street areinterconnected in this embodiment of my invention. Contacts 06 and 91parallel 92' and 93 and contacts 94 and 95 are in series with 90 and SI.Thus actuation of either ramp produces the same effect on the circuits.Fig. 2 or Fig. 2a, which disclose identical apparatus and circuits, showthe construction and wire arrangement in-detail of an electrical timelimiting control which is constructed according to this particularembodiment, and indicates also the electrical connections of the signalmeans, as well as a vehicle actuated means for each street. In Figs. 2and 2a,, 89 (Y) is a yellow light visible from both streets, 83 (3G) isa green light visible'from B-street, 84 (AR) is a -red light visiblefrom A-street, 85 (AG) is a green light visible from A-street, 86 (BR)is a red light visible from B street. Ramp arms I04 and I04 with theirassociated contacts represent vehicle actuated means on A-street andB-street respectively.

The control system includes the following relays: instantaneousoperating contacts relays 26, 21, 34, 35 and .36; oil dash-pot relays 28and 29 arranged to operate their armatures 30 seconds after their coilsare energized; oil dash-pot relays 30 and 3| arranged to operate theirarmatures seconds after their coils'are energized; and oil dash-potrelays 32 and 33 arranged to operate their armatures 2 seconds aftertheir coils are energized. All of the .oil dash pot relays release theirarmature immediately upon deenergization. The apparatus in the left halfof Figs. 2 and 2a controls the display of the A-street green signal 85and the B-street red signal 86. That in the right half controls thedisplay of the .B-street green signal 83 and the A-street red signal 84.These two groups of apparatus are interconnected in such a way as toprevent the simultaneous display of the green signals on both streetsbut to permit the green signal on either street to be displayed inresponse to traflic or by cyclic operation as will be more fullyexplained later. Furthermore these groups cooperate to display-a yellowsignal to both streets between changes in the green signal display aswill be explained street.-Assume a vehicle approaches on A street andactuates ramp 5, depressing bar I04, thereby opening contacts and BI andclosing contacts 92 and 23. The bar I04 may be any portion of a contactdevice and is shown as a lever pivoted about point I03 and held inposition by a spring I83' (see Fig. 3). Contacts 82 and 83 having beenengaged, relay 26 is energized through the circuit including wires I2land H8, switch I81, wire I I, contacts 82 and 83, wire I8, switch I81,wire I38, the coil of relay 26 and wires III' and H6. In Fig. 2 wire IIIconnects with wire II6 through wire III. Armatures 45 and 48 of relay 26are now moved into their operated position.

The engagement of armature 45 with contact 46' completes a holdingcircuit supplying positive power to the coil of relay 26 so that thisrelay will remain energized after the vehicle has passed ramp 5 andpermitted contacts 82 and 93 to separate again. This holding circuitincludes wire I48, armature 45, contact 46, wires H2 and I5I., contact6i, armature 58 and wires i 26 and I2I.

The engagement of armature 48 with contact 58 energizes relay 34 througha circuit including wires H6 and HI, armature 48 and contact 58, wiresH1 and H8, armature 88 and contact 88 of relay 36, wire I11, switch I85,wire N8, the coil of relay 38, wire I28, switch I85, wire I48, contact61, armature 65, and wires I6I and I2I. The armatures 1i and 11 of relay34 now assume their operated positions.

The separation of armature II from contact 12 extinguishes the yellowsignal 88 which had been energized through wires I2I and I42, armatureII, contact 12, wire I43, signal 88, wire I46, contact 15, armature 14of relay and wires I48 and H6.

The engagement of armature H with contact 13 energizes the A streetgreen signal 85 and the 13 street red signal 86 through wires I2I andI42, armature 1I, contact 13, wire I44, signals 85 and 86 in parallel,wires 81 and I I6.

The engagement of armature 11 with contact 18 completes a second holdingcircuit supplying positive power to the coil of relay 26. This circuitincludes wire I48, armature and contact 46 of relay 26, wires I I2 andI5I,.contact 18, armature 11 and wires I22 and I2I. The pu pose oi .thissecond holding circuit is to cause relay 26 to remain energized whilerelay 34 remains energized even though the first traced holding circuitfor relay 26 may be opened by the separation of armature 58 from-contact6| of relay 38 which will occur under circumstances to be explainedlater in these specifications.

The separation of armature 11 from contact 18 of relay 34 deenergizesrelay 33 which had been energized through a circuit including wires I2I.

and I22, armature 11, contact 18, wire I21, the coil of relay,33, wireI58, armature 51 and contact 58 of relay 28, wire I58, contact 63 andarmature 62 of relay 3| and wires I23 and H6.

Armature 68 of relay 33 now assumes its un operated position. Theseparation of armature 68 from contact 18 assures that relay 35 willremain deenerglzed, with the B street green signal consequently alsodeenerglzed, until relay 33 again operates which can occur only afterthe A street green signal has been extinguished and I a period of yellowcaution signal display has followed.

The engagement of armature 68 with contact 68 energizes timing relays 28and 38. The circuit through which relay 28 is energized includes wireI2I, switch point 24 and switch I8, wire I32, the coil of relay 28,wires I15 and I24, contact 68, armature 68 and wires .I68 and H6. Thecircuit through which relay 38 is energized includes wires H6 and I68,armature 68, contact 68, wires I24 and I16, the coil of relay 38, wireI38, switch I81, wire I2, contacts 88 and 8I associated with ramp arm 5in A street, wire I I, switch I81 and wires H8 and I2I.

Relays 28 and 38 thereupon begin to time their periods. If no othervehicle approaches from A street and contacts 88 and 8I consequentlyremain in continuous engagement, relay 38 will be continuouslyenergized. At the end of its time period, assumed here to be 10seconds-relay 38 will operate to terminate the A street green signaldisplay as follows. The separation of armature 58 from contact 68 opensthe circuit energizing the coil of relay 32. This circuit included WiresI2I, and I26, armature 58, contact 68, wire 3,

contact 56, armature 55, wire I I4, the coil of relay 32, wire II5,contact 82, armature 88 and wires 38 and II 6.

Armature of relay 32 now separates from contact 61 and make contact with66 thereby deenergizing relay 34 and through wire I 25 energizing relays28 and 3i. The circuit for relay 28 includes wire II6, switch point 25and switch I9, wire I55, the coil of relay 28, wires I14 and I25,contact 66 and armature 65 and wires IN and I2I. Positive power issupplied to the coil of relay 3I through the same circuit which feedsthe left coil terminal of relay 28 since wire I25 connects with bothwire I13 and wire I14. Relay 3| gets negative power through wire I88,switch I88, wire I3, contacts I33 and I34 associated with ramp arm I84,wire I4, switch I88'and wires I12 and H6. The deenergization of relay 34causes armature H to break from lcontact 13 and make contact with 12,thereby extinguishing green light 85 and red light 86 and lighting theyellow light 88. When relay 34 is de-energized, armature 11 breaks fromcontact 18 and makes contact with 19. Breaking contact. 18 opens theholding circuit and releases the armature of relay 26, thus dropping itback to its normal unoperated position. The other holding circuit forrelay 26, previously mentioned, is open due to the separation ofarmature 58 from contact 6 I of relay 38. Armature 11 making contactwith 18 energizes relay 33 through a previously traced circuit. Twoseconds after relay 33 is energized, armature 68 breaks from contact 68thereby de-energizing relays 28 and 38 and makes contact 18. Thedeenergizing of relay 28 has no effect on the circuit inasmuch as it hadnot been energized continuously for 30 seconds. The release of relay 38causes armature 58 to make contact with and H thereby energizing relay32 from wire I 26 through its previously traced circuit, which, after 2seconds, causes armature 65 to break from contact 66 therebyde-energizing relays 28 and 3| and make contact with 61. Thede-energizing of relays 28 and 3| has no efiect on the circuit, inasmuchas neither had been energized long'enough to operate. A yellow light isnow shown in both streets and the entire system has returned to itsoriginal condition.

Cass II.C0ntinu0us traflic on A-street with no traflicon B-street.If inthe preceding operation no cars had approached the intersection from Bstreet, but vehicles had approached on A street each actuating an Astreet ramp either (III 5 or 1 within 10 seconds of the previousactuashowing in B street, and in addition providing that current flowthrough the coil of relay 23, through armature 45 and contact 43 evenafter armature 11 shall have broken contact from 13. The purpose ofthisis brought out later. The 30 second time-limit relay 23 which wasenergized through its previously traced circuit at the same time that 10second relay 33 was energized, breaks the circuit between armature 55and contact 53 30. seconds after it is energized, thereby releasing the2-second time limit relay 32. Armature 35 breaks from contact 31 therebyinterrupting the current operating relay 34. Armature 1I breaks contactfrom 13 and makes contact with 12 thereby extinguishing green fight 35showing in A street and red light 33 showing in B street, and lightingthe yellow light 33. Armature 11 breaks from contact 13 but in thisparticular case does not interrupt the current operating relay 23because of the fact that said current is supplied through contacts 53and 3I on relay 33 which are connected in parallel with contacts 11 and13. The fact that relay 23 therefore remains energized causes lights 35and 33 to show after yellow light 33 has been lighted for 4 seconds asis explained in detail in the subsequent discussion, thus returning theright of way to A street after giving pedestrians'a 4 second period inwhich to cross A street. The actual operation of the circuit to producethis eflect is as follows. Armature 11 connects with contact 13, therebyenergizing the. 2 second time limit relay 33 as before described.- Twoseconds after relay 33 is energized armature 33 breaks from contact 33thereby opening the circuit to relays 23 and 33 through wire I24,whereupon armature 55 makes contact with '53, thereby energizing 2second relay 32. Two seconds after relay 32 is energized, armature35'makes con- "tact with 31, thereby energizing relay 34 whereuponarmature 1I breaks from contact 12 thus extinguishing the yellow lightand makes contact with 13 thus lighting the A street green light 35 andthe B street red light 33. This cycle of operations repeats as long asvehicles operate either ramp in A street within intervals of 10 secondsand none operate a ramp in B street.

- In the event that vehicles iailto operate either and contact 43, wiresI3I and I52, contact 34,.

A street ramp within an interval of 10 seconds, the subsequent operationis as described in Case I.

Cass IIL-One vehicle on A street followed within 10 seconds by onevehicle on B street.- Under this condition, the circuit operates as inCase I with the following changes. When relay 34 is de-energized throughthe breaking of arma ture 35 from contact 31, armature 11 makes contactwith 13. A vehicle operates either ramp ,4 or 3 in B street which causescurrent to flow through the coil of relay 21. The contacts of ramps 4and 3 control relay 21 just as contacts in ramps 3 and 1 control relay23, and they controlrelay 3I just as contacts in ramps 5' and 1 controlrelay 33. The actuation of ramp 3 causes contacts I53 and I54 to engagethus energizing relay 21 through a circuit including wires I I3 and I12,switch I33, wire I4, contacts I53 and I34.

wire I5, switch I33, wire I53, the coil of relay 21 and wires I33 andI2I. In Fig. 2 wire I33 connects with wire I2I through wire I33. Re-.lay 21 is now held in the operated position by current flowing throughwire I51, armature 41 armature 32 and wires I23 and H3. 11 makingcontact with 13 energizes relay 33 through contacts 51, u, u, and :2.Two soconds alter relay 33 is energized, armature 33 makes contact with13 thereby operating relay 35 through wires II3 and I33, armature 33,contact 13, wire I53, switch I33, wire I33, the coil of relay 35, wireI32, switch I33, wire I23, contact IIII, armature I33, wires I23 andI31, contact 53, armature 52, and wires I33 and I2I. The separation ofarmature 33 from contact 33 deenergizes relays 23 and 33. Relay 33 whichhas been operated now assumes its unoperated condition. The operation ofrelay 35 causes armature 14 to break contact from 15 thus extinguishingthe yellow light and to make contact with 13 thereby lighting the greenlight 33 on B street and red light 34 on A street. The circuit for theBstreet green and the A street red light includes wire 33, lamps 33 and34 in parallel,

wire I41, contact 13, armature 14 and wires I43 and H3. Thus the eflecthas been that the vehicle in A street has retained the right of way for10 seconds and at the end or this 10 second period, the signal has gonethrough the cautionary yellow period of way on B street. 5

' When relay 35 was energized armature 33 broke the circuit with contact32 and made contact ,with 3|. Breaking or the circuit between 33 and 32causes relay 32 to remain ale-energized after armature 53 has madecontact with 33 to an indication of right and 3|. When relay 32 wasoriginally deenergized by the separation of armature 59 from contact 33,as explained in Case I, armature made contact with 33 thereby energizingtime limit relays 23 and 3I the circuits for which have been tracedpreviously. Ten seconds afterrelay 3I was' energized, due to the factthat neither ramp in 13 street had been operated by a second vehicle,which would have de-energized relay 3|, armature 32 breaks contact with33 and 34 thereby de-energizing relay 33 thus permitting armature 33 tobreak contact from 13 and make contact with 33. The breaking of thecircuit between 33 and 13 de-energized relay 35, thus breaking contactbetween 14 and 13 thereby extinguishing green light 33 and red light 34and making contact between 14 and 15 thus lighting the yellow light 33.The separation of armature 33 from contact 3| deenergizes relay 21 whichhad been energized through a circuit including wires H3 and 33, armature33, contact 3I, wires I52 and I3I, contact 43, armature 41, wire I51,the coil of relay 21 and wires I33 and I2I. In Fig. 2 wire I33 connectswith wire I2I through wire I33. Armature 33 in making contact with 32energizes the 2 second relay 32 through contacts 55, 53, 33- and 53on'relays 23 and 33.- Two seconds after relay 32 is energized armature33 makes contact 31 and breaks from contact 33 therebyde-energizing timelimit relays 23 and 3I. In as much as relay 23 had not been energizedfor a suflicient length of time to I operate its armature, it has notacted to control the circuit. The de-energizing oi. relay 3| permitsarmature 32 to make contact with 33 and 34 thereby energizing relay 33,through armature 11 and contact- 13. Two seconds after Irelay 33 isenergized, armature 33 breaks from 33 thereby de-energlzing relays 23and 33' and makes contact with '13 so that relay -35 operatesimmediately when relay 21 is energized. -The circuit has now completedits cycle and has returned to the condition atthe beginning of Case I,and as shown in Fig. 2 and Fig. 2a.

Case IV.-Continuous trafl'ic on A street with one vehicle waiting on Bstreet-Under these conditions, the circuit operates as outlined in CaseII until a vehicle operates one of the ramps in B street. The opening ofthe circuit between contacts 55 and 58 which occurs 30 seconds afterrelay 28 is energized, de-energizes relay 32 causing armature 55 tobreak from contact and "make contact with 6. Connecting armature 55 withcontact 66 energizes relays 29 and 3|. Breaking the circuit betweenarmature 65 and contact 61 de-energizes relay 34 whereupon ar deenergizerelay 26 because current for relay 28 is supplied through wire I25,armature 59 and contact 5|, wires l5! and H2, armature l5 and contact 45and wire 0. In the meantime vehicle has operated one of the ramps on Bstreet energizing relay 2'41. Current to keep relay 21 energized aftersaid vehicle has crossed the ramp flows through armature H,- contact 48,contact 64, and armature 62. Armature 52 now makes contact with contact53. Armature H which made contact with contact 18 when relay 34 wasde-energized thereupon energized relay 33 through contacts 57, 58, 63,and 62. Two seconds after relay 33 is energized armature 88 breaks fromcontact 69 thereby de-energizing relays 28 and 3B. Armature 88, throughmaking contact with contact 18, now energizes relay 35 through switchI06 and contacts NH, I08, 53,

and 52. v Armature 14 now breaks from contact 15, thus extinguishing theyellow light, and makes contact with 16, thereby lighting the B streetgreen light and the A street red light 8i.

Armature 86 breaks from contact 82 and makes contact with 8| therebycausing relay 32 to remain de-energized despite the closing of contact55with contact 56. Armature 65 therefore remains in contact with 66keeping relay 29 energized and also relay 3| energized, inasmuch as thiscase assumes that a second car does not pass over a B street ramp. Hence10- seconds after relay 3! was energized armature 52 breaks from contact63 and contact 84 thereby de-energizing relay 33. Armature 88, of relay33, now breaks from contact 10 and makes contact with 59 therebyenergizing relays 28 and 30. Relay '35 is now de-energized through thebreak between armature 88 and contact 10. Armature I4 now breaks fromcontact thereby extinguishing the B street green light 83 and the Astreet red light 84. The yellow light 89 is now lighted through armaturel4 and contact 15. Armature at the same time breaks from contact 8|thereby de-energizing relay 21 inasmuch as armature 62 is not now incontact with 84. Armature 80 makes contact with contact 82 therebyenergizing relay 32 through contacts 55, 58; 59, and 80. Two secondsafter relay 32 is energized, armature 55 breaks from contact 58, therebyde-energizing relay 29 and relay 3 I ,and makes contact with 51, therebyenergizing relay 34 through switch I05, contacts 88, 88, wires H8 and II1, contacts 50 and 49. Armature 'H now breaks from contact 12extinguishing the yellow light and makes-contact'with I3 again lightingthe A street green light 85 and the B street red light 33. Armature TIalso breaks from contact 18 thereby insuring that relay 33 remainde-energized even though armature Blbe in contact with 58 and armature52 be in contact with 53 Armature Tl now makes-contact with 18 thusparalleling armature and contact 6|. The system has now returned to thecondition in which it was when the single vehicle actuated the ramp in Bstreet. In this description we have shown how continuous traflic in Astreet would be interrupted for a suflicient period to allow a singlevehicle from B street to use the intersection, and how right of waywould return immediately thereafter to A street in which the continuousstream of traflic had been interrupted.

Cass V.Continuous traific in both streets.- Under these conditions thecircuit operates as it did in Case IV to transfer the right of way fromA street to B street. But, continuous traflic in B street opens thecontacts in the B street ramps through which the currentenergizing relay3!- passes. Armature 52 therefore continues to make contact with 53 and6 .1. Relay 38 therefore remains energized until armature 5i breaks fromcontact 58 which will take place seconds after relay 29 is energized.The energizing of relay 28 is caused in accordance with the descriptiongiven in Case I. Armature 51 now breaking contact with 58 tie-energizesrelay 33. Armature 68 breaks contact from 10 and makes contact with 69thereby de-energizing relay and energizing time limit relays 28 and 30.Armature now breaks contact with 16, thereby extinguishing B streetgreen light 83 and A street red light contact 8| which action has noeffect on the circult inasmuch as this connection is also made byarmature 82 and contact 64. Armature 38 makes contact with.82 therebyenergizing relay 32. Two seconds after relay 32 is energized, armature65 breaks from contact 66 thereby causing the de-energizing or relays 29and 3i, thereby causing armature 5'Ijto make contact with 58. Armature65 makes contactwith 5?! thereby energizing relay 38 through switch I55,contacts 99,. 98, 50 and 48. Armature II now breaks from contact 12extinguishing the yellow light and makes contact with 13 lighting the Astreet green light 85 and the B street red light 88. Armature "breaksfrom contact 19 thereby causing relay 33 to remain de-energized eventhough armature 57 makes contact with 58 and armature 52 makes contactwith 63. Armature 11 now makes contact with 18 and the circuit hasreturned to the condition in which it was at the beginning of thisdescription.

Comnzorxon H.The operations described above under the headings Cases I,II, III. IV, and V, occur when the various switches are in the positionsshown in Fig. 2 and Fig. 2a of the drawings. It may be seen from aninspection of Fig. 2 or Fig. 2a that if switch I is closed,

relay 25 is continuously energized through wires |2l and H0, switch. l8,wire I39, the coil 01' relay 26, and wires Ill and Hi. In Fig. 2 wireIll connects with wire 6 through wire Ill thereby causing the right ofway to return to Y ii the switches are as shown except that switch I1 isclosed, the operation is as described in the last paragraph, except thatthe conditions described for A street and B street are interchanged.

CONNECTION IV.It can be seen that with both switches I8 and I1 closed,the right of way is granted alternately to each street and is held byeach street.for any period between 10 and 30 seconds. If no vehiclesactuate the ramp in a given street during a period of 10 seconds the 10second relay functions to yield the right of way. If, on the' otherhand, when said street is given the right of way, vehicles operateeither ramp in said street at intervals seconds, the 10 second relay isrepeatedly set back to its de-energized condition in which case the 30second relay functions to yield the right of way 30 seconds after it isgranted.

CONNECTION V.- It can be seen by an inspection of Fig. 2 or Fig. 2a ofthe drawings that if all the switches are as shown except that switch 2|makes contact with 38, then the opening of contacts 59 and 80 does notde-energize relay 32 unless relay 21 has been energized by a caroperating either ramp on B street. As long as relay 21 is deenergizedrelay 32 is connected to positive power through wire Ill, armature 55,contact 56, wire H3, switch 2|, switch point 38, wire I35, contact 54,armature 52, and wires I30 and HI. Hence the 10 second relay 30 does notoperate to cause the circuit to take'the right of way from A streetunless a vehicle has operated one of the ramps on B street, since 10seconds before B street last'lost right of way. With this connection theyellow signal is displayed to both streets in the absence of traffic.Any B street actuation will cause right of way to be granted thereto for10 seconds which period is extendable up to thirty second by subsequentB street actuations occurring at intervals of less than 10 seconds. An Astreet'actuation will cause right of way to be granted thereto for aperiod of thirty seconds in the absence of any B street actuation. Atany time after the first 10 seconds of this A street right of way perioda B street actuation will immediately cause the yellow signal to bedisplayed after which right of way will be granted to B street exceptthat A street actuations occurring at intervals ofless than ten secondscan maintain the A street right i of way up to a 30 second limit.

CONNECTION VI.-It can also be seen that with all switches as shown inFig. 2 or Fig. 2a of the drawings, except that switch 28 makes contactwith 31, the operation is as described above except' that conditions onA street and B street are interchanged. a

CONNECTION VII.--It can also be seen from an inspection of Fig. 2 orFig. 2a of the drawings that with all switches as shown except thatswitch I8 is moved from contact with 24 to 22, relay 28 is energizedonly when relay 21 shall have been Operated by a vehicle actuating oneof the ramps in 13 street. Therefore in the event of continuous trafllcon A street in which the A street ramps are operated at intervals ofless than 10 seconds, A street continuously holds the right 01. wayunless a vehicle on B street has actuated a ramp On that street since 10seconds before B street last lost right, of way, energizing relay 2!which energizes relay 28 through contacts 52 and 53. Thirty secondsafter relay 28 is energized, it iunctions to take the right of way fromA street. The cessation of A street traflic will of less than 10.whether or not an A street cause the right of way to be transferable toB street by action of relay 30 before the 30 second period or relay 28has expired.

CONNECTION VIH.-If the switches are as shown in Fig. 2 or Fig. 2a- 015the drawings, except that switch I9 is moved from contact with 25 to 23the conditions areas described in the above paragraph except that theconditions on A street and B street are interchanged.

CONNECTION IX.--If the switches are as shown in Fig. 2 or Fig. 2a of thedrawings except that switch 18 makes contact with 22 and switch 2| makescontact with 38, right of way remains with A street, once it is granted,continuously ramp is actuated until a vehicle on B street has operated aramp on B street since 10 seconds before B street last lost right ofway. I l

The operation of relay 21 de-energizes relay 32 by opening contacts 52and 54 providing the 10 second relay 3!) has already operated to opencontacts 59 and 60. In the event that a vehicle has operated the Astreet ramp within an in terval of 10 seconds, armature 59 will be incontact with 60 thereby supplying current to relay 32, despite theopening. of contacts 52 and 54. Upon the expiration of the 10 secondperiod following the operation of either A street ramp, armature 59breaks from contact therebydr energizing relay 32, relay 21 beingenergizeil which immediately causes the right of way to be taken from Astreet. If, on the other hand, vehicles on A street operate thezA streetramps at intervals of lessthan 10 seconds, thus causing armature 59 toremain in contact with 88, relay 28 operates to open contacts and 58therebyde-energizing .relay 32 thirty after the energizing of relay 21by a B -street ramp actuated by a vehicle.

be seen vfrom Fig. 2- or Fig. 2a. 9f the drawings that if the. sw itchesCONNECTION X.-It may are as shown, except that l9 makes contact withseconds 23, and 28 makes contact with 31, the operation is as describedin the above paragraph except that conditions in A street and B streetare interchanged.

CONNECTION XI.-It.can be seen from Fig. 2

or Fig.2a of the drawings that if the switches are as shown except thatswitch I8 is closed and switch 18 makes contact with 22, and switch 2|makes contact with 38, right of way reverts to A street, after eachyellow period suqaeeding a period during which B street held th .rlghtof way. A street then holds said right 0 way un-- til the end of theminimum period of 'lo'seconds of relay 39 after which right of way isinstantly yielded in response to B street. actuations if no A streetactuation has occurred during the preceding 10 seconds, or right of wayis yielded by the operation of relay 28, thirty seconds after relay 28is energized, if continuous trafflc on A street prevents the ing thesaid right of way. Relay 28 is' energized through contacts 52 madewhen'relay 21 is energized.

CONNECTION XlL-It may be seen from inspec-r tion of Fig. 2 or Fig. 2a ofthe drawings that if all switches are as shown except that switch I1 isclosed, switch 19 makes contact with 23, and switch 20 makes contactwith 31, the conditions are as outlined in the above paragraph exceptthat the conditions indicated for A street and B street areinterchanged.

CONNac-rroN XIII-It may be seen fom'inspection of Fig. 2 or Fig. 2a oithe drawings that 10 second relay from yield-' with the switches asshown except that switch 16 is closed and switch 2! makes contact with38 these conditions if no vehicles operate either of the B street rampsduring an-extended period, right of way is held by Astreet continuouslyexcept that every 30 seconds a yellow period of 4 seconds is introducedduring which time the A street green and the B street red lights areextinguished. Immediately following this period,

right of way returns to A street. This yellow period is inserted topermit pedestrians to cross A street. With the switches as described inthis case, if a vehicle operates a B street ramp, thereby energizingrelay 21, right of way is given to B street immediately after anintervening yellow 'period providing no vehicle has operated either ofthe A street ramps during the preceding seconds and provided that the Astreet minimum period of 10 seconds has expired. If, on the other hand,a vehicle has. operated either of the A street ramps during the 10second period immediately preceding the operation of the B street ramps,relay 32 is energized through contacts 59 and '60 despite the fact thatthe circuit is open between contact 52 and 54. Armature 59 is in'contact with 60 because under the above conditions relay 30'has not beenenergized continuously for 10 seconds. In the event that vehiclesoperate the A street ramps at intervals of less than 10 seconds relay 28functions 30 seconds after right of way is given to A street to yieldsaid right of way by de-energizing relay 32 through breaking the circuitbetween 55 and 5B. In this part of. the discussion, I have not tracedthe action beyond relay 32, since the operation subsequent to thede-energizing of relay 32 is always the same up to the point at whichrelay 34 turns off the A street green and the B street red and turns onthe yellow light, these being accomplished respectively by breaking ofarmature H from contact 13 and making of contact between H and 72. Thisaction takes place upon the de-energizing of relay 34 which isaccomplished through armature 65 breaking from contact 61 when relay 32is de-energized.

CONNECTION XIV.-It may be seen by reference to Fig. 2 or Fig.2a of thedrawings that if the switches are in the position shown except thatswitch I"! is closed and switch makes contact with 37, the operation isas described in the preceding paragraph, except that the conditions on Astreet and B street are interchanged. CONNECTION XV."I'he circuit is soarranged that if it is desired to disconnect the traflic actuated meansfor any reason, this can be accomplished by throwing switch I01- so thatit makes contact with 4!, 42, and 42', breaking contact from III, II,and I2, and throwing switch I08 so that it makes contact with 43, 43',and 44 breaking contact with l3, I4, and I5. Under these conditionsrelays and 21 are continuously energized through 4| and 42, 43 and. 44,and the coils of relays and 3! are disconnected from contacts l2 and I 3respectively, thereby causing said relays to be continuously deenergized. An

inspection of Fig. 2 of the drawings shows that independent of theposition of switches of i5, ll, I8, 19, 20, and 2|, the system operatesto give right of way alternately to. each street for 30 peats.

seconds, introducing a 2 second yellow period at each transfer. In thiscase, the action is as follows: Assume that the relays are as shown inFig. 2 and Fig. 2a and that switch I01 is thrown to this new positionbefore I08 is thrown to its new position. Hence relay 26 being the firstto be energized, gives right of way to A street in the following manner:Armature 48 breaks from 5! and makes contact with 50'thus connecting tothe power supply one terminal of the coil of relay 34 through wire H8armature 88, contact 99, and switch I05. The other coil terminaI ofrelay 34 is connected to the other side of the power supply througharmature 65 and contact 61 of relay 32. Relay 34 now being energized,armature ll now breaks from contact 12 thereby extinguishing the yellowlight and makes contact with 13 thereby lighting the A street greenlight 85 and the B street red light 85. Armature I1 breaks from contact19, thereby causing relay 33 to be de-energized. Armature 68 breaks fromcontact I0, thereby preventing any current from energizing relay 35, andmakes contact with 69 thereby energizing the coil 0! relay 28. Thirtyseconds after the coil of relay 28' is energized, armature breaks fromcontact 56, thereby de-energizing relay 32, whereupon armature breaksfrom contact 61 and makes contact with 66 thereby de-energizing relay 34and energizing relay 29. When relay 34 is deenergized, armature H breaksfrom contact 13, thereby extinguishing the A street green light and theB street red light, and makes contact with 12, thereby lighting theyellow light. Armature 11 makes contact with 19, thereby energizingrelay 33. Two seconds after relay 33 is energized, armature 88 breaksfrom contact 68, there- .by de-energizing relay 28. and causing armaturemakes contact with 89, thereby energizing relay '28. Relay 35 now beingie-energized, armature.

l4 breaks from contact [8, extinguishing the B street green and theA'street red light and makes contact with 15, thereby lighting theyellow light. Armature makes contact with 82, thereby energizing relay32. Two seconds after relay 32 is energized, armature 55 breaks fromcontact 88, de-energizing relay 29 and makes contact with 61, energizingrelay 34. Relay 34 now turns on the A street green and theB street redlights and extinguishes the yellow light. 'I'his cycle now re-CONNECTION XVL-If it is desired to disconnect the traflic actuated meansin A street and leave connected the traflic actuated means in B street,this may be accomplished by leaving the switches as shown in Fig. 2 andFig. 2a of the drawings,

except that switch Ill'lv is operated to the position making contactwith 4|, 42, and 42. Under this condition, right of way will remain on Astreet for a period of 30 seconds regardless of actuation of an A streetramp, and remains on B street fora period dependent upon the actuationof the B street ramps, varying from 10 to 30 seconds. Right of way "isgiven to B street following a yellow period only if a 3 street ramp hasbeen actuated since 10 seconds before B street last lost right of way.In the CONNECTION XVII.Likewise switch I08 may be operated to its otherposition instead of switch I01, thus producing the effect described inConnection XVI except that the condition on A street and B street areinterchanged.

The circuit is so arranged that manual control may be used. This isaccomplished as follows through the use .of switches I05 and I06. Toshow a yellow light in both streets, switches I05 and I06 are operatedto such a positionthat the blades make no contact. Thereupon, relays 34and 35 are de-energized and the yellow light is lighted through contactsII, 12, I4, and 15. To light the A street green and the B street redlights, the blades of switch I05 are thrown to the left contacts therebyenergizing relay 34 through wires I66 and I61, extinguishing the yellowlight by interrupting its circuit between H and I2, and lighting the Astreet green and the B street red through the contacts made betweenarmature 1| and contact 13. To light the B street green and the A streetred lights, the blades of switch I06 are thrown to the right contacts,thereby energizing relay- 35 through wires I64 and I65. Armature 14breaking from contact 15 opens the yellow light circuit, and armature 14making contact with I6 lights the B street green and the A streetredlights.

The circuit is so arranged that the yellow light can be turned on andall other signal lights ex-' tinguished either by closing switch I02shown in Fig. 2, and Fig. 2a or by applying power to the two wiresmarked To fire headquarters. This feature is introduced to provide foremergency control either at the control panel at the intersection, orfrom a distant point. Either of the last two described operationsenergize relay 36, thereby breaking contact between I00 and IN and 98and 99', thus deenergizing relays 34 and 35, causing armature 'II tomake contact with 12 and armature 14 to make contact with I5, therebylighting the yellow light and preventing any other signals from beinglighted except by man-' ual operation as previously described. Closingswitch I02 energizes relay 36 through wire I2I, switch I02, wire Ill andI69, the coil of relay 36, wire I68 and I10, switch I02 and wire H6.

The circuit is so arranged that if the right of way is yielded by onestreet due to the operation of the 30 second relay and not due to theoperation of the second relay, then the relay which is energized by theramps in the street which is just losing right of way, that is, relay 26for A street or relay 21 for B street is not de-energized as it is whenthe right of way is yielded by the operation of the 10. second relay,but remains energized thus providing that the right of way return tothis street immediately after a yellow period following the Thisarrangement is made because when the right of way is yielded by theoperation of the 30 second relay, a vehicle which has operated a ramp onthe street which is losing right of way has not had a full 10 secondperiod in which to cover the distance between the ramp and theintersection and to traverse the intersection. Thus it may be stoppedbetween the ramp and the intersection yielding by the other street;

by the red light. This circuit provides that the right of way return atthe earliest permissible moment to this car without the necessity offurther operation of a ramp in its street.

This effect is accomplished for A street as follows: The operation of 30second relay 28 to release relay 32 does not de-energize relay 26inasmuch as current is supplied through contacts 59 and 6 I If, however,the right of way is yielded by 10 second relay 30, contact is brokenbetween 59 and 6| thus de-energizing relay 26 when relay 34 isdeenergized.

Where, in this description, 9. change of switch positions is indicatedto produce a change in the efiect on the signal means of actuation of anA street trafiic actuated means, and another change of switch positionsis further indicated to produce the same change in the effect on thesignal means of actuation of a B street traflic actuated means, it isobvious that both changes in switch positions could be madesimultaneously, thus producing the aforesaid change in effect on thesignal means by traffic actuated means in both or either streets.

The term traflic actuated means or the like is used in thisspecification and in the appended claims in the sense of trafi'lcactuatable means or means adapted to be actuated by successive vehiclesrepeatedly. v

Whereas, I have described a single street traffic control systemembodying my invention, it is obvious that other arrangements embodyingmy invention may be constructed, and I do not wish to limit myself tothe particular embodiment described herein. I aim in the appended claimsto cover all modifications which are within the scope of my invention.

What I claim as new and desire to. secure by Letters Patent is: h I

1. In a highway trafiicslgnal system for intersecting lanes, right ofway signals for the respective lanes, traffic agtuated means in eachlane, a'timing device to regulating the periods of operation of thesignals, in accordance with trafiic demand among the intersecting lanesas revealed by the traffic actuated means, including means formaintaining periodic operation of the signals alternately in absence ofactuation of the traflic actuated means. 2. In an automatic trafiicsignal system for intersecting traffic lanes in combination, a pm ralityof signals at the intersection, electric control means for periodicallyoperating the signals including a plurality of interlocking relaysconnected in circuit for selectively operating the signals atpredetermined intervals in absence of traffic and traffic actuatablemeans for completing the circuits to certain of the relays whereby theperiod of operatio'n'of the signals may be changed by the passage oftraffic in either of the lanes.

3. A signal system for intersecting traflic lanes comprising means forindicating right of way signals for .the respective lanes, meansactuated by traffic in the respective lanes to operate the signalindicating means, means connected with the signal indicating means andthe traffic actuon said other lane and the operation-of the signal so asto interrupt a. continuous trafiic stream on said one lane and means foroperating the signal means in absence of actuation of the trafi'icactuated means in a periodic time sequence and traiiic lane sequence.

4. A system of trafiic control for use at the intersection of trafiiclanes, comprising a. traffic actuated means in each lane, signal meansincluding a caution signal and stop and go right of way signals for therespective lanes, and a control mechanism interposed between saidtrailic actuated means and said signal means for causing a cautionsignal to show in all lanes when no trafiic is immediately approachingthe intersection, said control mechanism including means for causing ago signal to indicate right of way to that one of the intersecting lanesupon which traffic shall first approach said intersection and to causesaid go signal to remain with this lane for a predetermined period aftereach vehicle thereon shall approach the intersection within apredetermined limiting period, means for causing the go signal to bewithdrawn from said lane when no vehicle approaches during one of thefirst mentioned predetermined periods, means for maintaining the gosignal when vehicles continue to approach at intervals of shorter timethan said first mentioned predetermined period and withdraw right of wayfrom said lane at the expiration of the second mentioned predeterminedperiod, means for granting right of way immediately or after.

a caution period to that traffic lane upon which a vehicle approachedsaid intersection subsequent to the approach of the vehicle which causedrightof way to be granted to the lane from which it was last withdrawn.

5. In a trafflc signal system, the combination with stop and go signalsat a highway inter-' section, of means including an instantaneous relayfor each highway and operated by a vehicle' on its highway, aninstantaneous signal relay for each highway, each connected to control astop and go signal to accord right of way to its associated highwayonly, a delayed action relay for each highway connected with theinstantaneous relays of that highway to time such accord of right ofway, and means including an operating circuit for each signal relayinterrupted by operation of the other signal relay and also interruptedby operation of its'connected delayed action relay at the end of thetime period of the latter to prevent the simultaneous operation of bothinstantaneous signal relays to operate stop and go signals.

6. In a traific signal system, the combination with stop, go and'caution signals at a highway intersection of means including aninstantaneous 6o relay for each highway connected to be energized by avehicle onits highway, an instantaneous signal relay for each highway,each connected to control a stop and g0 signal to accord right bf wayto'its associated highway only, adelayed 65 action relay for eachhighway connected with the instantaneous relays of that highway tooperate the signal relay responsive to operation fof the traflicactuated relay to maintain right of ,way accorded only to that highwayfor a pre- 70 {determined time period and to release said siginal relayat the end-of said time period, and imeans for actuating the cautionsignal when Pneither signal relay is so operated. 7. In a highwaytrafl'ic signal system for inter- 7 secting streets comprising aplurality of signal an intersecting street for interrupting thepredetermined period and for causing the desired signal to be given tosaid intersecting street and 10 timing means for reestablishing thesignal on the first street after a predetermined interval.

8. In a highway intersection traflic signal system comprising aplurality of right of way signal lights for the respective intersectinghighways, 15 a mechanism having a predetermined time rate of operationfor normally operating the signal lights in sequence and controlling theduration of the periods of operation of the signal lights in the absenceof traffic, said mechanism in- 0 cluding means for changing the normalduration of the period of operation of the signal lights in response totraiiic approaching the intersection.

9. In a highway signal system for intersecting 25 streets having asignal means for each street for indicating right of way, means forreceiving traffic presence indications from each street, including meansfor retaining the effect of such indications, and means for retainingthe eflect 30 of the first such traflic indication until the signalmeans has indicated the right of way signal to that street for acontinuous predetermined period after the last received traflic presenceindication from that street, and a timing mecha- 35 nism to time thecontinuous predetermined period through which the signal means indicatesthe right of way signal after the last received traflic presenceimpulse, said timing mechanism having an operating circuit and adaptedto be 0 energized to time its period by completion of said operatingcircuit and 'to reset to restart its timing responsive to interruptionof said operating circuit, and a control switch in said operatingcircuit and opened by each operation of 45 said traflic indicating meansto interrupt said operating circuit responsive to each trafilc presenceindication.

10.- In a,highway signal system for intersecting streetshaving a signalmeans-for each street for indicating right of way; means for receivingtraflic presence indications from each street, in-

cluding means for retaining the efiect of such indications, and meansfor retaining the efiect of the first such' traflic indication until thesig- I nal means has indicated the right of way signal to that streetfor a continuous predetermined period after the last received trafilcpresence indication from that street, a timing mechanism to time thecontinuous predetermined period so" through which the signal meansindicates the right 01' way signal'ai'ter the last received trafflcpresence impulse, said timing mechanism having an operating circuit andadapted to be energized to time its period by completion of saidoperating circuit and to reset to restart its timing responsive tointerruption of said operating circuit, and a control switch in saidoperating circuit and opened by each operation of said trailicindicating means to interrupt said operating circuit responsive to eachtraflic presence indication, and a second timing mechanism to controlthe maximum length of the time period which one street may be given theright of way indication by the signal means before the intersectingtrafiic lanes,

right of way indication is given to the other street.

11. In an automatic traffic signal system for in combination, aplurality of signals at the intersection, electric control means forperiodically operating the signals including a plurality of interlockingrelays connected in circuit forselectively operating the signals atpredetermined intervals, and trafiic actuated means for completing thecircuits to certain of the relays whereby the period of operation of thesignals in both streets may be changed by the passage of trafiic ineither of the lanes.

12. In an automatic intersecting trafiic lanes, in combination, aplurality of signals at the intersection, electric control means forperiodically operating the signals including a plurality of interlockingrelays connected in circuit for selectively operating the signals atpredetermined intervals in absence of traflic, and traffic actuatedmeans for completing the circuits to certain of the relays, wherebycontinuous traflic in one lane shall be interrupted to permit passage ofa vehicle in an intersecting lane within a predetermined time after thearrival of such vehicle, but only for a predetermined period to permitpassage of said vehicle.

13. In a vehicle actuated highway traflic signal system comprising aplurality of signal lights for intersecting highways, a mechanism havinga predetermined period of operation for normallights in sequence and lyoperating said signal duration of the periods fixing the sequence and ofoperation of the signal lights in absence of trafiic, said mechanismincluding means for changing the duration of the period and the sequenceof operation of the signal lights in response to trafiic approaching inat least one highway.

14. In a highway trafl'ic signal system com? prising a plurality ofsignal lights for intersecting highways, a mechanism having apredetermined period of operation for normally oper ating said'signallights and fixing the sequence and duration of the period of operationof the signal lights in absence of trafiic, said mechanism includingmeans for changing the duration of the period and the sequence ofoperation of the signal lights in response to trafiic approaching in atleast one highway, and means for preventing right of way signals beinggiven to traflic simultaneously from two or more lanes.

15. A trafiic signaling apparatus for two interfering traflic lanes andhaving, in combination, right of way indicating means for the respectivelanes, trailic actuated controllers, one in each of said lanes, a timingmechanism for limiting right of way indication in either lane between anoriginal, predetermined, minimum interval and a predetermined,"maximuminter-.

val of time by actuation of the ,controller forof way indication betweensaid lanes, said transfer of right of way being dependent upon actuationof a controller in either lane before the end of any minimum intervalindication or of any continuously prolonged minimum interval indicationof right of way, less than the maximum, begun in the other lane by theother controller.

traflic signal system for '16. In a. traffic signalling system forinterfering trafilc lanes, having means for displaying right of waysignal indications, signal timer means for normally cyclicallydisplaying said right of way indications successively to the severaltrafiic lanes, a vehicle responsive device on one of said lanes, anderable by response of said device to a vehicle onsaid one lane, torender said timer ineffective to normally display said indications, andto give the right of way indication to the said one lane.

1'7. In a traflic system for interfering lanes, a right of wayindicating means displaying said indication to each of said lanes forpredetermined times for the control of trafiic, a vehicle actuateddevice in one of said lanes, and means operable upon actuation of saiddevice when the said lane has the right of way for cooperating with thefirst named means to extend the? time of display of said indication tothe said one lane beyond the time predetermined by the first namedmeans.

18. In a traffic system for intersecting streets, a right of wayindication, means displaying said indication to each of said streets forpredetermined times for the control of traflic, a'vehicle actuateddevice in each street, and means operable upon an actuation of thedevice in the street having the right of way for cooperating with thefirst named means to extend the time of display of said indicationbeyond the time determined by the first named means.

19. In a traffic system for intersecting streets, 2. right of wayindication, means displaying said indication to each of said streets forpredetermined times ior the control of traffic, a vehicle actuateddevice in each street and means 0perable upon an actuation of the devicein the street having the right of with the first named means to extendthe time of display of said indication beyond the time determined by thefirst named means, and means to further extend the time of display ofsaid right of way indication upon subsequent actuations of the saiddevice in the street having the right of way occurring withinpredetermined intervals of each other.

20. A device as in the preceding claim further provided with means forlimiting such extended time of display of the right of way to the saidstreet to a predetermined maximum time.

, 21. A right of way indicating device for intersecting main and crossthoroughfares, controller means for normally periodically shifting theright of way indication from one thoroughfare to the other, means toarrest the operation of the controller so as to maintain the right ofway indication on the main thoroughfare,and meansv including a vehicleoperated device on the main thoroughfare to operate the controllerarresting means to maintain the right of way indication on the mainthoroughfare, and means operable within a predetermined time after thesaid arresting means has functioned to re-establish the periodic controlof the indication bythe said controller.

22. In a traffic signal system arranged at the intersection of a mainhighway and across road for regulating traflic, saidsystem comprising aplurality of signal circuits, one circuit including a signal to indicatestop and another to indicate go, a time control selective switch meansnormally associated withsaid circuits for alternately opening andclosingsame cyclically, vehicular actuated means for rendering the said supercontrol means op way for cooperating time control selective switch meanstemporarily inactive and to retain said go signal for the main highway,and a second time control switch means operable within a predeterminedtime after said selective switch has been rendered inactive to destroythe efiicacy of the said vehicle actuated means to retain the "go".signal for one complete cycle.

23. In a tra-filc signaling system arranged at the intersection of a'main highway and a crossroad for regulating trafllc, the systemcomprising-a plurality of signal circuits, said circuits including astop signal for each of said highways and a go signal for each of saidhighways, a time control selective switch means nor mally connected tothe said circuits for alternately opening and closing same cyclically,vehicular actuated means for rendering the said time controlledselective switch means temporarily inactive and to retain the said gosignal for the main highway, and a second time control means,ineifective during the display of the stop signal to the main highwayand operable to destroy the eflicacy of the said vehicular actuatedmeans to retain the "go signal for one complete cycle within apredetermined time after the said main highway go signal is retainedenergized through the arresting of the said selective switch means afterthe extinction of the display of the said last sto signal.

24. In a signal system for intersecting traffic lanes the combination ofright of way signals for the respective lanes, trafilc actuatable meansin each of the lanes, electro-magnetic means for opcrating therespective signals, electro-magnetic control means operated by actuationof the respective traffic actuatable means and an electric timecontrolled mechanism conmwted in circuit between the electro-magneticsignal operating means and the electro-magnetic control means of eachlane to operate the right of way signals alternately in a .predeterminedtime sequence in absence of actuation of said electro-magnetic controlmeans and including means to interrupt the predetermined time sequencefor a predetermined time interval in either lane responsive to actuationof the electro-magnetic control means for the latter lane.

25. In a trafiic signal system for intersecting highways, stop and gosignals for each of the respective highways, means including aninstantaneous relay for each highway operated by passage of a vehicle onits highway, an instantaneous signal relay for each highway to operate astop and go signal to accord right of way to its associated highwayonly, and a plurality of delayed action relays for each highwayconnecting the instantaneous relays of that highway to control the timeof such operation of the -stop and go signals by the signal relayresponsive to actuation of the traflic operated relay and meanscontrolled by said delayed action relays for interlocking theinstantaneous signal relays so as to prevent the operation of more thanone signal relayat the same time.

26. In a traffic signal system for intersecting lanes, a plurality ofright of way signal means for the respective lanes, time controlledmeans for operating the signal means normally in se-- quence at periodicintervals, means responsive to a. vehicle one one of the lanes forchanging the period of operation of one of said signal means by saidtime controlled means, and means forming a partot said time controlledmeans for prelanes, a plurality of go controllers in accordance withventing operation of right of way signals simultaneously in more thanone lane.

27. In a. trafllc signal system for intersecting signal means for therespective lanes, traflic actuated means for the respective lanes,timing mechanism connected with the tramc actuated means and the signalmeans to operate the signal means in one lane for a predeterminedperiod, said timing mechanism including means for interrupting the firstsignal and operating the signal of an intersecting lane at the end ofsaid period for another predetermined period in absence of traffic onsaid intersecting lane and means for restoring the go signal to thefirst lane at the end'of said second period in the absence of tramcthereon, and means responsive to actuation of said traific actuatedmeans in said intersecting lane to prolong said second period.

28. In a. vehicle actuated highway intersection trafiic signal systemcomprising a plurality of right of way signal means and a cautionsignal, trafllc actuatable means in the respective highways, timingmechanism having a'predetermined time rate of operation for normallyoperating alternately in a time sequence the right of way signal for onehighway and the caution signal in absence of traflic actuation, saidmechanism including means for changing the normal sequence of operationof the signals to include op-- rate of operation for normally operatingsaidv lights in sequence and controlling the duration of the periods ofoperation of the lights in absence of traflic, vehicle actuatable meansin at least on highway, said mechanism including means for increasingthe normal duraton of the period of operation of the signal light onsaid one highway in response to vehicle actuation thereon. v

30. Ina traflic signaling apparatus for two interfering trafllc laneshaving right of way indicating'means for the respective lanes, trafiicactuatable controllers in the respective lanes, and time controlledmechanism for operating the indicating means in the respective lanesalternately for variable time periods in response to actuation of therespective controllers in accordance withtrafiic demand; said mechanismincluding timing-devices individual to the respective lanes to limitoperation of the right of way indication in each lane between anoriginal predetermined minimum time interval and a greater predeterminedmax um time interval by actuation of the controller for such lane.

31. In a traflic signaling apparatus for two interfering trafllc laneshaving right of way signals for the respective lanes, traffic actuatablecontrollers in the respective lanes, and time controlled mechanism foroperating the signals in the respective lanes alternately for variabletime periods in response to actuation of the respective traflic demand,said mechanism including switching mechanism having alternate switchpositions for energizing the respective right of way signals, two timingdevices individual toeach lane one having a relatively shortpredetermined minimum time period and the other having a considerablylonger predetermined maximum time period, and connections between saidswitching mechanism and said timing devices to energize both said twodevices of either one lane for timing in the switch position energizingthe right of way signal for said one lane, and means includingconnections timing devices to control actuated by said two said switchmechanism to hold the latter in the last mentioned position during thetime periods of the respective two timing devices and at the of thelatter devices mechanism from said last transfer to the other potirningdevice havto release the switch mentioned position for sition, each saidminimumw ing a connection with the traflic actuated 0011- troller of itsassociated lane and being adapted to reset its timing period responsiveto actuation of such controller.

- 32. In a trafiic signaling apparatus for two interfering lanes havinga caution signal and right of way signals for the respective lanes,trafflc actuatable controllers-for the respective lanes, and timecontrolled mechanism for operating the right of way signals in therespective lanes alternately for variable time periods in response toactuation of the respective controllers in accordance with traflicdemand, and operating the caution signal for a brief period interveningthe alternate right of way signal periods, said mechanism includingtiming devices individual to the respective lanes to control operationof the right of way signal in each lane individually so as to limit suchoperation between an original predetermined minimum time interval and agreater maximum time interval by actuation of the controller for suchlane, and additional timing devices for the respective lanes connectedto be operated by the respective first named timing devices at the endof timing interval of the latteronone lane to operate said cautionsignal for a brief time interval and at the end of the last named timeinterval to initiate such control of the right of way signal by thetiming devices for the other lane.

33. In a trafiic signaling apparatus for two interfering trafiic laneshaving right of way signals for the respective lanes, trafiic actuatablecontrollers in the respective lanes, and time controlled mechanism foroperating the signals in the respective lanes alternately for variabletime periods in response to actuation of the respective controllers inaccordance with traflic demand, said mechanism including switchingmechanism having alternate switch positions for energizing therespective right of way signals, two timing devices individual to eachlane onehaving a relatively short predetermined minimum time period andthe other having a considerably longer predetermined maximum timeperiod, and connections between said switching mechanism and saidminimum timing devices to energize said minimum device of either onelane for timing in the switch position energizing the right of waysignal for said one lane, and switching mechanism and said maximumtiming devices and including switch means operated by the respectivecontrollers to energize the maximum timing device of either one laneresponsive to traflic actuation on the other lane in the right of wayswitch position of said one lane, and

means including connections actuated by saidsive to actuations ofconnections between. said nism to hold the position during the timeperiods of the respective two timing devices and at the end of theperiod of either of the latter devices to release the switch mechanismfrom said last mentioned position for transfer to the other position inresponse to actuation of the controller for the other lane, each saidminimum timing device having a connection with the tramc actuatedcontroller of its associated lane and being adapted to reset its timingperiod responsive to actuation of such controller.

34. In a trafilc-signaling system, the combination of signals operableto indicate the right of way to several intersecting streetssuccessively and for simultaneously indicating stop to the others,signal switch mechanism operable to several positions to energize thenecessary signal combinations in each of its several positions grantingthe right of way to said intersecting streets respectively, saidmechanism including switches operated for so energizing the severalsignals in the respective right of way positions and an interlockingconnecting between said switches to prevent concurrent operation of theswitches for the respective right of way signals, vehicle-actuated andtiming switches for the respective streets and operable respectivelyresponsive to actuations of said vehicle-actuated devices in theintersecting streets to control the positioning of said signal switchmechanism and for maintaining said signal switch mechanism in a selectedposition granting right of way for a minimum time period responsive to asingle actuation of a vehicle-actuated device.

35. In a traflic signalling system, the combination of signals operableto indicate the right of way to several intersecting streetssuccessively and for simultaneously indicating stop to the others ofsaid streets, signal switch mechanism operable to several positions toenergize the necessary signal combinations in each of its severalpositions granting theright of way to said intersecting streetsrespectively, said mechanism including switches operated for soenergizing the several signals in the respective right of way positionsand an interlocking connection between said switches to preventconcurrent operation of the switches for the respective right of waysi'gnals, vehicle-actuated devices in each of said streets, and timingswitches for the respective streets and operable respectively responsaidvehicle-actuated devices to operate said signal switch mechanism toassume a predetermined position granting right of way responsive to anactuation of a vehicleactuated device in one of the intersectingstreets, to hold said signal position for a predetermined minimum timeperiod and to hold said signal switch mechanism in said position for apredetermined maximum time period responsive to successive actuations ofsaid vehicle-actuated device, said actuations being spaced from-eachother a time period less than said minimum period.

36. In a traificesignaling system the combination of signals positionedat the intersection'of two thoroughfares and operable to alternatelyindicate the right of way to each of said thoroughfares respectivelywhile indicating stop to the other, vehicle-actuated devices in each ofsaid thoroughfares, relays responsive to actuations of said vehicledevices in fares respectively and operable to record the preslatter inthe last mentioned devices in each of said streets,

switch mechanism in said the thoroughence of vehicles at theintersection on the thoroughfares nothaving the right of way, a timingated responsive to the joint action of said timing switches to energizesaid signals to maintain the right of way on one thoroughfare for apredetermined minimum time period by one timing switch responsive to asingle actuation of a said vehicle-actuated device in that thoroughfareand to transfer the control of said signals to the second of said timingswitches at the end of this period, said signal switch mechanismincluding switches for so energizing the signals to grant right of wayto the respective thoroughfares and an interlocking connection'betweensaid switches to prevent concurrent operation of the switches for therespective right of way signals.

37. In a traihc signalling system for two intersecting streets, a rightof way signal for one of the streets, a switch operable for energizingsaid signal, a trafiic actuated device for said one street, and a timingswitch for said one street, a second right of way signal for the secondstreet, a second switch operable for energizing said sec- -ond signal, atrafiic'actuated device for said second street, and a timing switch forsaid second street, and operating mechanism for the signal switches andhaving two alternate interlocked positions, one for operatingonly thefirst mentioned switch to accord right of way to the first street andthe second position for operating only the second switch to accord rightof way to the second street, and connections between said mechanism andthe two sets of timing switchesand traii'ic actuated devices for the twostreets to control shift of said mechanism from either one position tothe other to accord right of way responsive to actuation of therespective devices in the street not having right of way, and tomaintain said mechanism for a minimum time period by one timing switchin either one position to which said mechanism is so shifted in responseto a single actuation of one trafiic actuated device and to releasecontrol of said mechanism to the other traflic actuated device atcompletion of the time period of the last mentioned one timing switchfor shift from the last mentioned one position of said mechanism to theother position responsive to actuation 'of said other traific actuateddevice.

38. In a trafiic signalling system for two intersecting streets, a rightof way signal for one of the streets, a switch operable for energizingsaid signal, a tramc actuated device for said one street, and a minimumperiod timing switch and a maximum period timing switch for saidone-street, a second right of way signal for the second street, a secondswitch operable for energizing said second signal, a tramc actuateddevice for said second street, and a minimum period timing switch and amaximum period timing switch for said second street, and operatingmechanism for the signal switches and having two alternate interlockedoperating positions, one

second position for operating only the secondswitch to accord rightof'way to the second street, and connections between said mechanism and-respective minimum and maximum timing switches for one street and fromthe traflic actuated device for the second street to shift saidmechanism from said one position to said second position responsive totrailic actuation of the second traffic actuated device and tocompletion of timing by either one of said one minimum and said onemaximum timing switches, an operating connection for said mechanism fromthe minimum and maximum timing switches for the second street and fromthe traffic actuated for said one street to shift said mechanism fromsaid second position to said one position responsive to trafficactuation of said one device and to completion of its timing by eitherone of said second minimum and said maximum timing switches, and acontrolling connection between the traific actuated device on eachstreet and the minimum timing switch for that street to interruptcompletion of the timing of the minimum timing switch to maintain rightof way beyond the minimum period and up tothe maximum period by repeatedtrafiic actuations.

39. A traflic control system for use at the intersection of a pluralityof trailic lanes, comprising a vehicle-actuated means in each laneplaced for actuation by vehicles approaching the intersection; a cautionsignal and right of way signal means for each lane, a controlling meansinterposed between said vehicle-actuated means and said signal means,said controlling means including means to operate a right of way signalto that lane from which vehicles shall first approach said intersection,means for maintaining said right of way until a vehicle approaches saidintersection from another of said intersecting lanes and holding saidright of way thereafter for a predetermined period after the approach ofeach vehicle on the first lane within another predetermined limitingperiod, means to withdraw said right of way upon the expiration of oneof. the first mentioned predetermined periods after such approach of avehicle in said other lane when vehicles cease approaching on said firstlane for an interval greater than said first mentioned predeterminedperiod, and means for withdrawing the right of way at the expiration ofthe second mentioned predetermined limiting period after such approachof a vehicle on said other lane when vehicles constantly approach saidintersection at intervals less than proached said intersection afterright of way was granted to the first lane and to provide a period ofcaution signal opera-tion between such withdrawal and such grant ofright of way.

HENRY A. HAUGH, JR.

